//定义懒加载插件
import { useIntersectionObserver } from "@vueuse/core";

export const lazyPlugin={
  install(app){
    //懒加载指令逻辑
    app.directive("img-lazy", {
      mounted(el, binding) {
        //el:指令绑定的那个元素 img
        //binding:binding.value 指令等于号后面绑定的表达式的值 图片url
        const {stop}=useIntersectionObserver(el, ([{ isIntersecting }]) => {
          if (isIntersecting) {
            //进入视口区域
            el.src = binding.value;
            stop()
          }
        });
      },
    });
  }
}